1. Field of the Invention
The present invention relates to a resin molded product including an optical element used in an observation optical system or an imaging optical system, a manufacturing method of the same, and a die for the resin molded product.
2. Description of the Related Art
In general, a two-color molding technique is used as one of methods of integrally forming an optical element such as a lens and an adjacent member adjacent thereto from a resin material. For example, Japanese Patent No. 3820137 discloses the two-color molding method between an optical element and an adjacent member.
This example uses a metal die for primary molding to primarily mold a primary molded product and a metal die for secondary molding to secondarily mold a secondary molded product. In the metal die for primary molding, a first cavity for a primary molded product is formed by a male metal die and a first female metal die. The same male metal die as the male metal die for the primary molding is used also as the male metal die in the secondary molding. A second cavity for a secondary molded product is formed by the male metal die and the second female metal die. The male metal die includes a fit engagement portion to fitly engage with the molded member (primary molded product).
When molding a two-color molded product, at first, first resin is injected into the first cavity in the metal die for primary-molding described above, to primarily mold the optical element (primary molded product). Thereafter, the male metal die and the first female metal die are separated. At this time, the optical element is fitly engaged in the fit engagement portion of the male metal die. By inserting this male metal die into the second female metal die of the metal die for secondary molding, the second cavity is formed therebetween. A two-color molded product is obtained by secondarily molding an adjacent member connected to an optical element by injecting the second resin into the second cavity.